How this calculator works
A milligram is one millionth of a kilogram. NIST defines the international avoirdupois pound as exactly 0.45359237 kg, so one pound contains exactly 453592.37 mg. The table puts small laboratory masses into pounds without changing the material or assuming a density.
Formula
lb = mg / 453592.37; mg = lb x 453592.37. The defining factor is exact.
Worked example
A 500 mg sample is about 0.00110231131 lb. In reverse, 0.25 lb is exactly 113398.0925 mg.
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Frequently asked questions
How many milligrams are in one pound?
Exactly 453592.37 mg in an avoirdupois pound.
Does lbs mean the same unit as lb?
Yes. lb is the usual unit symbol; lbs is a common informal plural.
Can I use this for precious metals?
This page uses the ordinary avoirdupois pound. Troy ounces belong to a different mass system.